Keystone air conditioner display and lights work, but the unit does not respond to remote control commands.

Steps:

• Replace batteries: Install fresh, correctly oriented batteries in the remote.
• Clear line of sight: Ensure there is no obstruction between the remote and the AC's IR receiver window on the front panel.
• Test remote: Point the remote at a smartphone camera and press buttons; you should see the IR LED flash on the screen. If not, the remote is faulty and should be replaced.
• Receiver check: If the remote works but the unit does not respond, the IR receiver module or display board may be defective and require replacement.